These are fret numbers, as @Tim already said, but they do not necessarily indicate full or partial barré. They indicate position. This sometimes does mean a barré, sometimes it indicates just the playing position on the fretboard.
PS: as requested in the comment: the position is indicated by a "C" followed by a roman numeral, i.e. "CIV" for fourth position or "CVII" for seventh position. It indicates the "root fret" for the hand position on the fretboard, which sometimes means to play a full or partial barré, sometimes it just indicates the finger position.
For instance: playing a am7 chord as A-x-g-c'-e'-x (5th fret, A-string and e-string muted)) would also be 5th position without any barré involved.